I think there are other factors involved here.
First of, the level of QB play had increased for us this year.

Last year, we only faced one QB that is difficult to put pressure on in all 16 games; that was Brees.

This year, we've already faces 3 in Manning, Rodgers, and Stafford.

Last year we also faced some bad QB like Gabbert (twice).
Even Gabbert this year is "much" better than last year.

We saw an old K Collins who was never mobile to start with;
Big Ben is known to keep the ball longer than he should;
Campbell is a wash with the combo of himself and Cutler this year, not even counting the condition of the field.

Even Sanchez is a mobile QB, more than the other QBs we faced last year that has not been mentioned.